The solar plexus is located approximately in front of the diaphragm in the upper abdomen. It is composed of many smaller plexi like the hepatic plexus and gastric plexus.
A plexus is a group of nerves concentrated into one area. The solar plexus, which is really called the celiac plexus, is a bundle of important nerves in the abdomen area that is connected to many major organs. It is called the solar plexus because the nerves radiate out from the center of the plexus like rays from the sun. When a person receives a blow to the area, the stimulation of the solar plexus can cause the diaphragm to spasm and make it temporarily difficult to breathe.